Arca-Artes - Injection Desuperheater - IOM...This technical description is intended for the service personnel of ARTES VALVE & SERVICE GmbH and the specialised personnel that have

TECHNICAL DESCRIPTION

Desuperheater


Page 2 of 21

Contents

1 Identification ..............................................................................................................................3 1.1 ID plate of the fitting ......................................................................................................... 3

2 General .......................................................................................................................................4 2.1 Use................................................................................................................................... 4 2.2 Intended use .................................................................................................................... 4 2.3 Warning symbols ............................................................................................................. 5

3 Description .................................................................................................................................6 3.1 Design of the desuperheater............................................................................................ 6

3.2 Mode of operation of the desuperheater.......................................................................... 7 3.3 Mode of operation of the temperature control.................................................................. 9

4 Assembly instructions ............................................................................................................11 4.1 General .......................................................................................................................... 11 4.2 Preparations for mounting.............................................................................................. 12

4.2.1 Mounting to connecting piece ............................................................................................ 12 4.2.2 Installation location ............................................................................................................ 12 4.2.3 Installation in the line ........................................................................................................ 13

4.2.4 Actuator.............................................................................................................................. 14 4.2.5 Insulation of the desuperheater ......................................................................................... 14

5 Startup ......................................................................................................................................15 5.1 Startup steps.................................................................................................................. 15 5.2 During operation ............................................................................................................ 16 5.3 Dismounting from the pipe line ...................................................................................... 16 5.4 Disassembly of the desuperheater ................................................................................ 18 5.5 Inspection....................................................................................................................... 18 5.6 Assembly ....................................................................................................................... 19

6 Tests .........................................................................................................................................19 6.1 Pressure test.................................................................................................................. 19 6.2 Leak test ........................................................................................................................ 20 6.3 Functional test................................................................................................................ 20

7 Spare parts list.........................................................................................................................21

Created: Checked/released: Document: Status/Rev.:on: 21.04.2004 on: 14.07.2004 by: K/Schüler by: QS/Mathes TB_Einspritzkuehler_Rev_03.doc 03


Page 3 of 21

1 IDENTIFICATION

1.1 ID PLATE OF THE FITTING

Steam Water Opening angle 10) °

DN / PN 1) 5) Serial no. 11)

Operating temp.

2) °C 6) °C Year of manufacture

12)

Operating pressure

3) bar(a) 7) bar(a) Tag no. 13)

Material 4) 8)

KVS value 9) m³/h Tel.: 030 / 91204710 - Fax: 030 / 91204720 C

1) Nominal width and nominal pressure rating: steam connection

2) Max. operating temperature: steam

3) Max. operating pressure: steam

4) Material of fitting housing (steam connection)

5) Nominal width and nominal pressure rating: cooling water connection

6) Max. operating temperature: cooling water

7) Max. operating pressure: cooling water

8) Material of connection flange: cooling water

9) Flow characteristic (KVS value) of the fitting

10) Opening angle of the fitting

11) Serial number of the fitting

12) Year of manufacture of the fitting

13) ID no. (Tag no.) of the fitting



Page 4 of 21

2 GENERAL

2.1 USE

The desuperheater is used to control the temperature of steam and hot gases in power plants, che-

mical plants etc.

In this description, water is used as medium, for the sake of simplicity. The description analogously

applies to other media.

The injected water is atomised to a micro-fine state by means of nozzles.

The integrated ball valve with the ball/seat ring system seals off the injection water.

To minimise wear, the ball is used as first throttle level, in special cases. This is noted in the valve

data sheet, with the remark “2-stage pressure reduction”.

The fitting is installed directly in the respective steam or process line.

2.2 INTENDED USE

The desuperheater is exclusively intended for regulating the temperature of steam and hot gases by

means of injection of cooling water. Any other or additional use has to be agreed upon contractually.

This technical description and the operating data listed on the ID plate (see section 1.1 “ID plate of

the fitting”) have to be observed.

Adherence to local accident prevention and environmental protection regulations, as well as all

customer specifications, is an integral part of intended use.

The safety information in the technical description has to be read prior to transporting, installing or

repairing the desuperheater. The technical description has to be stored with care, so that its informa-

tion is available at all times.

The technical description has to be accessible to the operating and service personnel at all times.



Page 5 of 21

This technical description is intended for the service personnel of ARTES VALVE & SERVICE GmbH

and the specialised personnel that have been trained by ARTES VALVE & SERVICE GmbH.

If the repair tasks are performed by untrained personnel, the guarantee automatically becomes void.

2.3 WARNING SYMBOLS

Safety instructions and warnings are aimed at preventing danger to the life and health of users or

maintenance personnel, and at preventing material damage. They are highlighted by means of the

signal terms defined here. Furthermore they are designated by warning symbols (pictographs) whe-

rever they occur. The meanings of the implemented signal terms are as follows:

DANGER!Immediate danger to health and life or danger of extensive mate-

rial damage in the event of non-adherence to the instructions.

CAUTION!Dangerous situation

Instructions on avoiding damage

NOTE!Help, suggestions or hints

regarding a procedure.



Page 6 of 21

3 DESCRIPTION

3.1 DESIGN OF THE DESUPERHEATER

Fig. 3.1 Sectional view of the desuperheater

Pos. 1 - Housing Pos. 7 - Nozzle stem Pos. 31 - Packing

Pos. 2 - Packing housing Pos. 8 - Pressure piece Pos. 32 & 33 - Seals

Pos. 3 - Cooling water connection Pos. 9 - Gland follower Pos. 35 - SR seal

Pos. 5 - Seat ring Pos. 20 - Indicator Pos. 40 - Stud bolt

Pos. 6 - Ball stem Pos. 25 - Frame Pos. 41 - Hexagon nut

Pos. 15 - Bushing

Pos. 16 - Adapter ring

Pos. 17 - Nozzle

Pos. 18.x - Nozzle insert

Pos. 30 - Seal

Fig. 3.2 Sectional view of the nozzle



Page 7 of 21

3.2 MODE OF OPERATION OF THE DESUPERHEATER

The temperature of steam and hot gases is controlled by regulating the cooling water injected into a

steam or hot gas current.

With the desuperheater, it is possible to precisely control the injection quantity in accordance with the

characteristic curve, by means of a special, individual nozzle control system that has been adapted to

the operating conditions.

The implementation of a nozzle system with integrated swirl inserts enables constant, very fine ato-

misation of the cooling water in all load ranges. Water is supplied to the individual nozzles through

boreholes in such a way that the characteristic curve of the valve has no steps.

The order in which the nozzles open has been determined by the design and construction. The nozz-

les located in the middle of the desuperheater are the first to inject cooling water.

The desuperheater has to be integrated into the pipe in such a way that the nozzle that opens first is

located in the middle of the pipe. This ensures that the water is injected into the area with the highest

flow speed, even when the flow rate is low. The distance between the first nozzle and the pipe wall is

the largest. This largely prevents thermoshock at the pressurised steam line or insufficient perfor-

mance in the case of low steam flow rates.



The ball valve that is integrated into the desu-

perheater blocks off the cooling water.

The sealing requirements for this blocking

valve are specified in the contract. By default,

the fitting complies with the requirements for

control fittings as set out in VDI/VDE 2174

(the leakage flow, calculated for uniform con-

ditions, is less than 0.05% of the KVS value).

Compliance with DIN/EN 12266-1 has to be

specially arranged.

Fig. 3.3 Integrated bal

When the different

differential pressur

desuperheater.

The differential pre

5 bar. If the differe

les should be expe

The nozzle wear c

system is used as

characteristics ach

Created: Checkon: 21.04.2004 on: by: K/Schüler by:

Ball

Page

l valve - ball/seat ring system

ial pressure between the

e is applied at the nozz

ssure between the ste

ntial pressure increases

cted.

an be minimised by usi

first regulated throttle s

ieved by means of the n

To minimise the nozzle

must be taken that the

the stellite. In power pla

sible to use stellite.

ed/released: Document:14.07.2004 QS/Mathes TB_Einspritz

Seat ring

The ball/seat ring system is a pure metal seal

and therefore can seal tightly for a long dura-

tion of time.
Pressure
8 of 21

steam or hot gas and the cooling water is low, the entire

le systems, due to the very low loss of power within the

am or hot gas and the cooling water should be at least

to values higher than 30 bar, increased wear at the nozz-

ng multi-stage pressure reduction. Here the ball/seat ring

tage. The contour integrated into the ball and the control

ozzles form a unit.

wear, it is possible to use nozzles made of stellite. Care

quality of the injected water does not cause corrosion of

nts that apply the so-called “combi-mode”, it is not permis-

Status/Rev.:

kuehler_Rev_03.doc 03


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3.3 MODE OF OPERATION OF THE TEMPERATURE CONTROL

If no special agreements have been made, the control system of the desuperheater and actuator unit

is not included in the scope of supply provided by ARTES VALVE & SERVICE GmbH.

The subsequent text describes a typical temperature control. This is only an example and is not bin-

ding for specific applications:

Three temperature sensors, located downstream of the desuperheater, measure the ACTUAL steam

temperature and send the value to the control system. If the SETPOINT and ACTUAL temperature

value deviate, the actuator of the desuperheater is activated.

Usually a 4 - 20 mA control signal is used. The fitting is closed at 4 mA.

The actuator sets the desuperheater to the required position, in accordance with the change in the

control signal. The stem rotation causes the nozzles to be switched on and off and the appropriate

control characteristic is applied to control the injection quantity in accordance with the requirements

of the valve's characteristic curve. This process continues until the SETPOINT and ACTUAL value

match.



Page 10

Normally feedforward

control is achieved

through input of valve

settings for the steam flow

control valves or “pre- and

post-superheater” tempe-

ratures.

Actuator unit

Pos Temperature control

r

Temperature s

Direction of

flow Steam

Fig. 3.4 Schematic diagram - Mode of operation of the te

Electric, pneumatic or hydraulic variable spee

The actuator and desuperheater are subjecte

We recommend that filteri

vent contamination of the

vals.

ARTES VALVE & SERVICthe fitting caused by fore

Created: Checked/released: Document:on: 21.04.2004 on: 14.07.2004 by: K/Schüler by: QS/Mathes TB_Einspritzku

Measuring transducer

Inlet

itioners

If no special agreements

have been made, ARTES
Cooling wate
of 21

VALVE & SERVICE

GmbH does not provide

any warranty for the cor-

rectness of the control

system (because it is not

part of the scope of deli-

very).

ensor

mperature control

d drives can be used as actuator for the desuperheater.

d to a functionality test prior to shipment.

ng screens are installed in the cooling water line to pre-

desuperheater and to increase the maintenance inter-

E GmbH does not accept any liability for damage to ign objects.

Status/Rev.:

ehler_Rev_03.doc 03


Page 11 of 21

4 ASSEMBLY INSTRUCTIONS

Non-adherence to the following assembly instructions voids the warranty claims.

4.1 GENERAL

Desuperheater The desuperheater may only be installed by the service personnel of ARTES

VALVE & SERVICE GmbH or by trained specialists.

Care must be taken that no piping forces can act on the desuperheater.

The flange seals at the steam flange and at the cooling water connection ha-

ve to be selected in accordance with the operating data. The manufacturer's

specifications have to be observed.

Actuator The instructions in the technical description of the actuator have to be obser-

ved. If it is not included as appendix, it has to be ordered.

The factory settings of the actuator may not be modified.

The max. permissible ambient temperature for the actuator may not be ex-

ceeded (observe the operating instructions of the actuator!).



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4.2 PREPARATIONS FOR MOUNTING

4.2.1 Mounting to connecting piece

Prior to mounting the desuperheater, the following points have to be checked and

documented, because the lance of the desuperheater must not touch other com-

ponents:

1. ACTUAL bore diameter of the connecting piece of the steam or hot

gas line

2. ACTUAL hole circle diameter of the boreholes in the connecting pie-

ce of the steam or hot gas line

3. Distance from sealing surface of the connecting piece to the centre

of the steam or hot gas line

4. Form and position of the connecting piece

5. Impermissible weld root penetration has to be eliminated.

6. The lance may not make contact with the steam line or thermoshock

pipe on the opposite site of the steam connecting piece. Thermal ex-

pansion during operation has to be taken into account. If necessary,

a borehole has to be made in the thermoshock pipe opposite.

4.2.2 Installation location

1. Choose an installation location where the desuperheater is always accessible.

2. If the fitting and the actuator together weigh more than 30 kg, a possibility to attach a

chain hoist has to be provided for mounting the fitting in the steam line.

3. The actuator has to be easily accessible for adjustments.

4. There has to be a straight pipe of at least 5 x dCL upstream of the cooling water flange

(dCL - diameter of cooling water line).

5. There has to be a straight steam pipe of 5 x dSL upstream of the desuperheater (dSL - dia-

meter of steam line).



Page 13 of 21

The specifications for the straight outflow section downstream of the fitting and the distance to the temperature sensors are listed in the data sheet of the valve. These minimum distances have to be observed.

4.2.3 Installation in the line

The following points have to be taken into account when installing the desu-

perheater:

1. No forces and torques from the supply line of the injection medium

may act on the desuperheater.

2. Care must be taken that no contaminations from the line can damage

the desuperheater. The line section between the filtering screen and

the desuperheater has to be checked. In new plants, it is recommen-

ded to design appropriately shaped weld seams.

3. When the fitting is mounted to the connecting piece, ensure that the

axis of the desuperheater is aligned with the axis of the connecting

piece. There has to be an even annular gap of at least 2.0 mm bet-

ween the connecting piece and the lance.

4. The screw connections at the steam and cooling water flange have

to be tightened crosswise and evenly, with the torque required for the

selected seal and the respective application.

The water is injected through the nozzles, in the direction of flow of the steam!



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4.2.4 Actuator

The desuperheater is supplied with a mounted actuator. If it is required to dis-

mount the fitting and actuator, the following instructions have to be observed. The

technical description supplied by the manufacturer of the actuator also has to be

observed.

1. The desuperheater has to be “OPENED” or “CLOSED” to a defined

position by means of the actuator. In this position, the signal feed-

back of 4 - 20 mA (normally) and the final position switch have been

preset at the factory. This final position has to be used for re-mounting the fitting and actuator! Mark the position (for example

through a coloured marking).

2. During dismounting and mounting, take care that no forces and tor-

ques affect the spindle of the desuperheater. Otherwise damage to

the ball of the ball stem (pos. 6), the seat ring (pos. 5) and the nozz-

le system (pos. 15, 16, 17, 18.x & 30) cannot be excluded. During

the mounting procedure, the screws have to be tightened crosswise

at the required torque.

Never loosen the screw connection and turn the actuator on the desu-perheater. The nozzle stem (pos. 7) will also be turned, with the result that the nozzles will not be activated correctly any more!

4.2.5 Insulation of the desuperheater

It is recommended not to enclose the steam flange and the cooling water flange in

insulation. This makes it easier to detect leaks and no damage to the insulation,

caused by leaks, occurs.

However, due to the high temperatures of the components, care must be taken that

the components cannot be touched.

The insulation has to be fitted in such a way that the max. ambient temperatures for

the actuator, as prescribed by the manufacturer, are not exceeded.



Page 15 of 21

The sealing of the injection water line at the seat ring is suitable for a max. tempera-

ture of 300 °C. It has to be ensured that no heat accumulation can occur at the

housing due to the housing being insulated or due to a installation location that

does not offer sufficient air circulation.

5 STARTUP

The operating conditions stipulated in the purchasing contract have to be ob-

served. Else the warranty becomes void.

The ID plate of the desuperheater lists the design data for the steam and water

side. These values may not be exceeded.

5.1 STARTUP STEPS

1. All screw connections have to be inspected while they are cold.

2. The actuator has to be run through its entire range while it is cold. If there is stiffness of

movement, the packing has to be loosened.

The feedback signal and the final positions, as well as the intermediate positions (if appli-

cable) have to be inspected and calibrated. The manufacturer's specifications and the o-

perating manual of the actuator have to be observed.

3. The injection water line has to be vented at the highest point, else water hammer can da-

mage the fitting. If the desuperheater itself is located at the highest point in the injection

water line, the line can be vented into the steam line, via the fitting. To do so, the desu-

perheater has to be completely open.

4. When the operating temperature has been reached, all screw connections have to be in-

spected again and retightened if necessary.

Check that the packing has been tightened to the correct torque. At operating

temperature it is possible that the packing blocks the spindle. This is entirely nor-

mal. If this occurs, loosen the packing until the spindle is not blocked any more.

Here, as always, care must be taken to ensure tightness against leaks.



Page 16 of 21

5.2 DURING OPERATION

During operation, the desuperheater has to be checked for leaks to the outside.

The frequency of the inspections depends on the plant requirements, however they should be per-

formed at least every six months.

The revision intervals for the desuperheater primarily depend on the differential pressure between the

water and the steam, and the water quality. These criteria are responsible for wear to the compo-

nents. Normally servicing tasks are performed after 16,000 operating hours.

It is recommended that the desuperheater is always serviced after 24,000 operating hours.

Damage to the pressurised components is almost entirely impossible when proper operation is adhe-

red to.

Only ARTES VALVE & SERVICE GmbH personnel or trained specialists may

perform the servicing tasks, else the warranty becomes void.

5.3 DISMOUNTING FROM THE PIPE LINE

1. Switch off the section of the plant. The regulations applying to the plant have to be obser-

ved.

2. Obtain written confirmation that the plant is not pressurised (release).

3. Check the on-site temperature. The temperature of the components have to be lower than

the temperature permitted by the relevant authorities.

4. Carefully loosen the flange on the water and steam side.

5. Remove from the steam line.

The actuator may not be used to lift the entire unit. If required, dismount the

actuator and fitting separately (also see section 4.2.4 “Actuator”)



Page 17 of 21

The packing housing can be used to lift the desuperheater by means of a

strap.

6. A Euro pallet can be used for transport purposes. Caution! Secure properly.



Page 18 of 21

5.4 DISASSEMBLY OF THE DESUPERHEATER

All flange connections have to be marked prior to loosening

them and have to be refit at the same positions later.

1. Dismount the actuator.

2. Dismount the cooling water connection.

3. Dismount the nozzles. Complete a nozzle proto-

col prior to disassembly (see Appendix)

4. Remove the unit formed by the frame (pos. 25),

the packing housing (pos. 2) and the ball stem

(pos. 6).

5. Dismantle into individual parts.

6. Clean all parts.

5.5 INSPECTION

All components have to be subjected to a visual inspection.

The degree of wear incurred on components that are sub-

ject to wear has to be determined.

Fig. 5.1 Disassembly

If it cannot be guaranteed that the components will have high enough quality until

the next service stop, the components have to be exchanged.

Use only original spare parts.



Page 19 of 21

5.6 ASSEMBLY

Prior to assembly, the contact pattern of the seat ring (pos. 5) on the ball of the ball stem (pos. 6) has

to be inspected. Regrind with diamond paste (800 grit) if required.

All bushings (pos. 15) have to be ground in on the nozzle stem (pos. 7) at the position where the as-

sembly will take place later (800 grit).

For assembly, reverse the steps described at 5.4 “Disassembling the desuperheater”.

When assembling the nozzle system (pos. 15, 16, 17, 18.x & 30), make sure that the entire surface of

the bushings (pos. 15) make contact with the nozzle stem (pos. 7). Canting can cause grooves on the

nozzle stem. This can lead to leaks.

When the nozzles are screwed in (pos. 17), the pure graphite ring (pos. 30) has to be pressed for-

ward; subsequently the nozzle (pos. 17) has to be loosened again by a quarter turn. The torque of

the ball stem (pos. 6) and nozzle stem (pos. 7) have to be checked during assembly of each nozzle

(pos. 17) (stiffness).

6 TESTS

6.1 PRESSURE TEST

The desuperheater has been subjected to a pressure test when it was new. The test pressure can be

found in the documentation.

After the service tasks have been completed, the pressure test has to be repeated.

The steam flange of the housing is not subjected to a pressure test.

The pressure test for the steam flange is done in the plant.



Page 20 of 21

6.2 LEAK TEST

It is necessary to differentiate between two leak tests:

Leak test for the ball/seat ring system

Leak test for the nozzles

The leak tightness of the fitting, in other words the ball/seat ring system, is done with water at a test

pressure of 6 bar.

Among themselves, the nozzles have to seal tightly, so that no undesirable drops of water resulting

from untight nozzles can lead to thermoshock in the steam line during operation with partial load.

The nozzle tightness is checked with water, at a pressure of 6 bar. To do so, the desuperheater is

opened slowly. The nozzles then have to consecutively open and close in the prescribed order. If

water escapes at the thread of the nozzle, the nozzle has to be tightened slightly. The ease of mo-

vement of the stem system (ball stem (pos. 6) & nozzle stem (pos. 7) may not be influenced. If ne-

cessary, regrind the bushing (pos. 15).

After the leak test has been completed, secure the nozzles against being turned to the wrong positi-

on. This is done by means of two punches.

6.3 FUNCTIONAL TEST

The functionality of the desuperheater is tested together with the actuator. The torque, the feedback

signal and the displacement switches are configured.

The technical description supplied by the manufacturer of the actuator has to be observed.

The technical description of the actuator can be found in the appendix.



Page 21 of 21


7 SPARE PARTS LIST

The listed spare parts are recommended by the manufacturer.

Pos. Designation Material

5 Seat ring 1.4122

6 Ball stem 1.4122

7 Nozzle stem 1.4301 / 1.4057

8 Pressure piece 1.4541

9 Gland follower See parts list in documentation

15 Bushing 1.4122

16 Adapter ring 1.4122

17 Nozzle 1.4122 / Stellite

18.x Nozzle insert 1.4541

Seal assembly

VEREENIGINGTel: 011 397 2833

Fax: 011 397 4700

DURBANTel: 031 579 2593

Fax: 031 579 2562

E-mail: [email protected]

Exports: [email protected]

Documents

Arca-Artes - Injection Desuperheater - IOM...This technical description is intended for the service personnel of ARTES VALVE & SERVICE GmbH and the specialised personnel that have